Preparation and Development of An Immunochromatographic Test for early Detection of Canine Visceral Leishmaniasis: A Preliminary Study

Abstract

Background: Canine visceral leishmaniasis (CVL), caused by Leishmania infantum (L. infantum), is a serious parasitic disease. Domestic dogs in endemic regions act as primary reservoirs for the parasite. Early diagnosis, control, and regular screening of dogs are essential for effective disease management. This study aims to develop a practical, low-cost immunochromatographic test (ICT) for detecting specific anti-Leishmania antibodies in domestic dogs. Methods: Overall, 93 canine serum samples were collected from endemic and non-endemic areas of CVL in Iran. Rabbit anti-canine antibodies were conjugated with gold nanoparticles, and strips were coated with Leishmaniaantigens. A drop of serum was added to each strip, and a positive result was indicated by two red lines. The validity of ICT for the detection of CVL in the field was determined with comparing to direct agglutination test (DAT) as gold serological test on 40 sera with anti-Leishmania antibodies at titers ≥1:320 considered as positive control as well as 53 sera with no anti-Leishmaniaantibodies including 10 collected from healthy dogs and 43 from other infectious diseases considered as negative control sera. Results: A sensitivity of 82.5% (CI 95%.78.1-86.9) and specificity of 90.5% (CI 95%. 87.7-92.5) were found at a 1:320 cut off titer when DAT confirmed cases were compared with negative control. The agreement (0. 871) was found between ICT and DAT using kappa analysis. Conclusion: A relatively good agreement was found between ICT and DAT. Further researches on test validation with larger populations in endemic and non-endemic areas of CVL, is recommended.